10-√n≥0 n∈[0,100)
Alegi patratele perfecte din acest intervali si deduci n prin incercarii
n=0 10-0 =/ patrat perfect
n=1 10-1 =9 pp se accepta
n=4 10-2=/pp
n=9 10-3=7 =/pp
n=16
10-4=6 =/pp
n=25 10-5=5=/pp
n=36 10-6=4 pp
n=49 10-7=3=/pp
n=64 10-8=2 =/pp
n=81 10-9=1=pp
n=100 10-10=0 pp
A={0,1,36,81,100}
2. {,121 169,196}
3 y√2∈Q <=> y=o +> membrul drept e 0.Deci si membrul stang e 0 lx-1l=0 => x=1
